Orthotic Insert Device

ABSTRACT

An orthotic insert device has a first portion generally underlying the plantar surface of the heel fat pad of the calcaneus of a wearer&#39;s foot when the insert is placed in a corresponding shoe. The device has a second portion which is located and sized to generally underlie the mid-foot of the wearer. The first portion under the heel is less rigid, that is, more compressible, than the second portion underlying the mid-foot. As a result, the device not only decreases the force felt on the heel, but also acts to offload the force from the heel toward the mid-foot, especially during the impact phase of a person&#39;s gait. By off-loading the heel and transferring weight to the mid-foot, force otherwise felt in the region of the calcaneus is dissipated over a much larger surface area, including the mid-foot.

FIELD

This disclosure relates to orthotic devices and, more particularly, toan orthotic insert device.

BACKGROUND

There exists a variety of orthotic inserts, ranging from custom orthoticinserts prepared by medical practitioners to off-the-shelf varieties,such as foot pads, cushioning insoles and the like. Certain of theseinserts may be geared more toward improving arch support, so that thearch undergoes fewer traumas or stress, especially during running orother physical activities. Other shoe inserts and orthotics may addresslong-term general comfort issues and focus on improving the cushioningof the associated shoe or athletic footwear, again, with the goal ofreducing foot fatigue which may develop when the wearer is “on theirfeet” for extended periods of time. Still other inserts may focus onreturning energy during running or walking, by providing a springinessor spring force, generally directed through the user's heel, with thethought that such energy return would improve speed or athleticperformance. Prior art inserts often do not adequately factor in foot orheel anatomy or the associated dynamics.

The orthotic inserts of the current art suffer from various drawbacksand disadvantages. Accordingly, there is a need for an improved orthoticinsert device to address disorders of the heel and hind-foot and theirassociated discomforts.

SUMMARY

In one implementation, an orthotic insert is adapting to alleviate heelpain and includes two or more portions. The first portion is located andsized to underlie and elevate the heel, and has a corresponding firstcompression load deflection. The second portion is anterior to the firstportion, and is located and sized to underlie the mid-foot. The secondportion has a compression load deflection value greater than that of thefirst portion, which, in practical terms, means that the second portiondeflects less readily than the first portion under comparable force. Inthis way, the first portion is less rigid than the second portion, andthe insert thereby offloads vertical force from the heel toward themid-foot during a person's gait.

In another variation, the first portion of the orthotic insert isconfigured to extend from the heel counter of a corresponding shoe inwhich the insert may be received, to a zone underlying the plantarsurface of the foot just distal to the insertion of the plantar fasciaon the medial tubercle of the calcaneus. The second portion extends froma zone underlying the plantar surface just distal of the insertion ofthe plantar fascia on the medial tubercle of the calcaneus, extendingmedially and laterally, substantially underlying the calcaneal cuboidjoint, and tapering distally to a location proximal to the metatarsalheads.

In still further implementations, the first portion has a compressionload deflection of 400 to 1000 pounds per square inch (psi), whereas thesecond portion anterior to the first portion has a compression loaddeflection of between 600 to 1,200 psi.

In still further implementations, an orthotic insert consistsessentially of two zones of material. The first zone having compressionload deflection of 400 to 1000 psi and the second zone having acompression load deflection of 600 to 1,200 psi. In yet anotherimplementation, the two zones of different compression load deflectionhave opposing boundaries which slope to form a third transition zone,the third transition zone having a compression load deflection betweenthe corresponding compression load deflections of the first and secondzones.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure herein will be more readily understood with reference tothe drawings, in which:

FIG. 1 is an elevational, cross-sectional view showing an orthoticinsert device according to the present disclosure, which has beeninserted into a wearer's shoe, the orthotic insert device underlying thewearer's foot inserted in said shoe;

FIG. 2 is a bottom plan view of a typical wearer's foot;

FIG. 3 is an isometric view of the orthotic insert device of FIG. 1according to the present disclosure;

FIG. 4 is a top plan view of the orthotic insert device of FIGS. 1 and3;

FIG. 5 is a side elevational view of the orthotic device of FIGS. 1, 3,and 4;

FIG. 6 is a bottom plan view of the orthotic insert device of FIGS. 1, 3and 4, and 5.

DETAILED DESCRIPTION

Referring to the drawings, FIG. 1 shows one implementation of anorthotic insert device 21 adapted to be inserted into a wearer's shoe28. Device 21 includes an upper or dorsal surface 51 adapted to underlieplantar surface k of the wearer's foot, and a lower plantar surface 52which generally faces the shoe insole. Device 21 includes two portions,a first portion 23 generally underlying the plantar surface of the heelfat pad below calcaneus d, and a second portion 25 located and sized togenerally underlie mid-foot h of a human foot i. First portion 23underlying calcaneus d is less rigid, that is, more compressible, thansecond portion 25 underlying mid-foot h. As discussed below, theforegoing and other characteristics of this implementation of device 21cause not only a decrease in the force felt on the heel, but also anoffloading of vertical force from the heel j toward the mid-foot h,especially during the impact or propulsive phases of a person's gait. Byoffloading the heel and transferring weight to the mid-foot, forceotherwise felt in the region of calcaneus d is dissipated over a muchlarger surface area, including mid-foot h.

Time and force applied to the heel area are shortened and reduced,resulting in a decrease or elimination of discomfort associated withmany disorders of the heel and hind-foot. Disorders which may beadvantageously treated using this implementation of device 21 include,without limitation, the following: heel pain, plantar fasciitis, heelspur, bone contusion, hematoma, heel bursitis, chronic inflammation ofthe heel pad, Severs disease (calcaneal apophysitis), growth plateinjury, post-traumatic pain, soft tissue injury, bone loss, puncturewound, tendonitis, achilles pathology, equinus, arthritis,enthesiopathy, and limb length discrepancy.

Portions 23 and 25, in this implementation, are advantageously sized andlocated relative to certain anatomical features of the foot, illustratedin FIG. 2. In general terms, foot i includes a lower or plantar surfacek, and device 21 at least partially underlies plantar surface k as shownin FIG. 1. Heel j includes calcaneus d and a heel fat pad generallydisposed between calcaneus d and the corresponding plantar surface ofheel j. Calcaneus d includes a medial tubercle c into which the proximalor posterior ends of plantar fascia (not shown) are inserted, suchinsertion region being generally shown by reference letter “b” in FIG.2. The plantar fascia (not shown) extend from insertion region b tometatarsal heads a.

Mid-foot h extends distally or anteriorly from heel region j andincludes therein the calcaneal cuboid joint, laterally, locatedapproximately in the region indicated by e in FIG. 2, and the navicularcuneiform joint, medially (not shown). Feet are also characterized ashaving a corresponding longitudinal arch f and sagittal plane arch g, asshown in FIG. 2.

Referring now to FIGS. 3-6, various features of orthotic insert device21 are shown and described with reference to each other and theanatomical features of the foot. Structurally, portion 23 has aposterior or proximal edge 24 adapted to lie adjacent or near heelcounter 26 of corresponding shoe 28 (FIG. 1). Portion 23 includes anupper or dorsal surface 29 and an opposite, lower surface 31. Uppersurface 29 forms a proximal or posterior portion of the overall uppersurface 51 of device 21. Portion 23 is comprised of resilientlycompressible material which extends from proximal edge 24 forward andends in an anterior or forward distal surface 33. The thickness ofportion 23 narrows as portion 23 extends forward or distally in thelongitudinal direction, such that surface 29 slopes slightly downwardlyfrom the horizontal in the orientation shown in FIG. 5, thereby locatingsurface 29 near proximal edge 24 higher relative to surface 29 at distaledge 35. Heel j (FIG. 1) is elevated by resiliently compressible portion23.

As seen in FIGS. 3 and 4, portion 23 includes a forward or distalsurface 33 which extends in an arc between lower surface 31 and uppersurface 29 of portion 23. The arc begins at a location 34 at the lowersurface 31, and extends to a distal edge 35 on upper surface 29. Assuch, the first portion 23 extends from heel counter 26 first in agenerally planar fashion to a zone 37, slightly distal to the insertionpoint b of the plantar fascia into the medial tubercle, and then beginsto taper as it extends further distally along arcuate surface 33. Thetapering of first portion 23 continues to distal edge 35 at or near thecalcaneal cuboid joint e and sagittal plane arch g.

Second portion 25 is generally arc-shaped in longitudinal cross-section,and has upper and lower surfaces 47, 41 (respectively), extending from aproximal edge 42 to a distal edge 45. Portion 25 has a proximal orposterior portion 39 which opposes and extends along correspondingdistal surface 33 of portion 23, as seen in FIG. 3. Proximal portion 39extends from proximal edge 42, just distal of the insertion point of theplantar fascia in the medial tubercle of the calcaneus, medially andlaterally.

Upper surface 47 may be configured to extend in arcs or slopes, havingdifferent radii of curvature or degrees, as appropriate, as it extendslongitudinally from back to front. In this implementation, upper surface47 curves upwardly as shown in FIG. 3 from its proximal edge 42 to anapex region 49. In this way, portion 25 substantially underliescalcaneal cuboid joint e. From said apex 49, surface 47 extends distallyand slopes or arcs generally downwardly, defining three regions 46, 48,and 50 on upper surface 47, each having corresponding downward slopes orarcs, terminating proximal to metatarsal heads a, where upper surface 47terminates along with lower surface 41 to form forward edge 45. Portion25 underlies a substantial portion of the mid-foot h, generally about 75to 100%. Upper surface 47, from its apex 49 and forward to edge 45,forms part of upper surface 51 of insert device 21 which is designed tounderlie plantar surface k of the user's foot. The posterior portion ofdevice upper surface 51, as discussed previously, is comprised of uppersurface 29 of portion 23.

Upper surface 47 of portion 25 makes substantial contact with at least asubstantial portion of the bony and soft tissue structure of the foot.Second portion 25 includes a transverse plane curvature 53 adapted tomake substantial contact with longitudinal plane arch f. Portion 25likewise includes a sagittal plane curvature 55 adapted to makesubstantial contact with a corresponding sagittal plane arch g of thefoot.

Device 21, as illustrated herein, has been designed with reference tothe left foot. The same principles described herein for the left footand left insert would apply to a device for the right foot, in mirrorimage. Of course, device 21 may include suitable contouring or otherfeatures, and may likewise comprise a pair of orthotic inserts for theleft and right foot.

In this implementation, portions 23, 25 are formed of suitable materialto have a compression load deflection value for portion 23 which is lessthan that of portion 25. In other words, portion 25 is more rigid thanportion 23, and thereby deflects less readily than first portion 23under comparable force. Suitable compression load deflections forportion 23 may be selected from the range of 400 and 1,000 psi, and asuitable compression load deflection value for portion 25 may beselected to be greater than that of portion 23, and in the range of 600to 1,200 psi, whereby the second portion is more rigid than the firstportion.

In one preferred implementation, the operative elements of first portion23 may be formed substantially of foam or rubber, whereas those ofsecond portion 25 may be substantially a plastic or polymeric material,so that portion 25 is generally more rigid or resilient than portion 23.In other implementations, portions 23, 25 may be formed of the samematerials processed to achieve the differing ranges of compression loaddeflection set out herein, as well as one or more foam or plasticmaterials, mixed, layered or otherwise blended.

In terms of durometer of portions 23, 25, using the 00 durometermeasurement scale described in ASTM D2240, first portion 23 may have adurometer of about 70 to about 80, and second portion 25 has a durometerof about 90 to about 100, or alternatively, may have a still higherdurometer. In relative terms, the durometer of portion 23 may be lessthan that associated with portion 25 by about 10 to about 30, or,alternatively, a still greater relative difference in durometer values.

The material or materials forming portions 23, 25 may includeresiliently compressible materials. In one possible implementation,material or materials are formed from a thermoset process, wherebyportion 25 is more resilient than portion 23. In one implementation, thethermoset material of portion 25 is selected so that portion 25 resistsdeflection beyond 7% in the range of anticipated uses of insert 21.Other materials are likewise suitable for either or both of portions 23,25, including foam, plastic, thermoplastic elastomers, vulcanized orthermoset rubber, elastomeric materials, cellular materials, metal,wood, cellulose, paper, or still other non-foam or non-plasticmaterials, alone or in combination.

According to one alternative implementation, portions 23 and 25 arepredominately formed of thermoset foam materials, with portion 25 beingcorrespondingly more rigid, and formed into a dome shape, with a planarlower surface substantially coplanar with lower surface 31 of portion23.

Whatever individual material or combinations of materials may beselected for given applications of the present disclosure, theresiliency and compression load deflection characteristics may be variedor tuned to the gait cycle of a particular wearer, average wearer, orclass of wearers (for example, obese individuals, diabetics, men, women,children, and the like).

In the disclosed implementation, for example, upper surface 29 ofportion 23, when in its unloaded state, is generally higher relative toupper surface 47 of portion 25. When device 21 is in use, and thussubject to weight of the wearer and forces of the gait cycle, theinterplay of the differing resiliency or compression characteristics ofthe two portions 23, 25 may reduce pain and foster other therapeuticbenefits as described herein. So, when a wearer is walking (or running,climbing, etc.), heel j either impacts the ground or is “pushing off” orpropelling off the ground. During such gait phase or phases, theincreased compressibility of portion 23 relative to portion 25 mayresult in upper surface 29 of portion 23 being compressed downwardlyrelative to the sole of the shoe, by the wearer's heel, such that itlies in a horizontal plane generally below at least apex region 49 ofportion 25. Otherwise stated, during heel-strike phases of a person'sgait cycle, the respective durometers of the first and second portions23, 25 are selected to compress first portion 23 vertically more thansecond portion 25 to off-load heel-strike force toward the mid-foot. Therelative compressibility (or its converse, rigidity) between portions23, 25 is thus selected or tuned to “offload” force otherwise felt bythe heel j toward mid-foot h.

The rates at which portions 23 and 25 compress relative to each othermay also be tuned to correspond to the expected time heel j will beexposed to impact or propulsive force during the gait cycle. Otherwisestated, durometer selection for portions 23, 25 may factored into thetiming of the wearer's gait cycle, either on average, by class, or for aparticular person.

Portions 23, 25 are suitably secured to remain in position relative toeach other, such as by suitably located adhesive effective for foammaterials, by heat bonding or other fusing techniques, or by combiningportions 23, 25 with integrating covers, tapes, or adhesive layers.

Still other materials are likewise suitable for implementing thefeatures of this disclosure and the scope of this disclosure is notlimited by those materials specifically mentioned above. It is likewiseappreciated that material may be combined with other materials ofvarying compressibility and resiliency and that the durometer range maybe tuned or otherwise varied to include different ranges for portions23, 25 or more than just the two ranges discussed herein. Similarly,suitable fabric, edges, or coverings or materials may be eitherengineered into the materials disclosed herein or arranged so as toencapsulate or overlie portions 23, 25. Such additional features arelikewise part of the present disclosure.

Furthermore, the durometer range of portions 23, 25 may be varieddepending on the weight of the intended user. As such, it is possiblethat different durometer ranges may be appropriate for device 21intended for obese individuals on the one hand, or those below averageweight on the other. Similarly, different durometer ranges may beappropriate for devices 21 for men, women, or children. In someapplications, the durometer of portion 23 may be selected tosubstantially equilibrate the heel of the intended wearer duringwalking, whereby device 21 assists in causing heel j to “float” duringthe heel strike and contact phases of a person's gait.

The size of orthotic insert device may be varied depending on thewearer's foot size, gender, and similar such factors. Arcuate surfaces,arches, depressions, and other shaped features and contouring maylikewise be incorporated into device 21 described herein, withoutdeparting from the scope of coverage of this disclosure.

In one suitable implementation, insert 21 measures about 14.5 cm inlength from the rearmost portion 57 of the proximal edge 24 to forwardedge 45 of insert 21, with upper surface 29 of portion 23 extendingabout 6.3 cm of that length, and upper surface 47 of second portion 25extending the balance of about 8.2 cm. Device 21 has an average width ofabout 7 cm. In addition to varying the dimensions of device 21 toaccommodate different foot sizes, it will be appreciated that theoverall outer dimensions of device 21 will be contoured and otherwiseconfigured for insertion into a wearer's shoe, and so the overall lengthand width given herein may be varied depending on the amount ofcontouring appropriate for the intended application.

Portion 23 may have a thickness of about 1.5 cm at rear 57 of edge 24,with upper surface 29 of portion 23 sloping gradually relative to lowersurface 31 so that the relative distance between upper and lowersurfaces 29, 31 is about 1.2 to 1.3 cm when measured near apex 49.Arcuate surface 33, in this implementation, forms a boundary betweenportions 23, 25, extending over a linear distance of about 5 cm andhaving a radius of curvature of about 6.5 cm.

Portion 25 has a thickness of about 1.2 to 1.3 cm at apex region 49,tapering distally through a pair of arcuate regions 46 and 48 havingrespective radii of curvature of about 16 cm and 13 cm, respectively.Apex region 49 extends longitudinally over a distance of about 1 cm.

In the implementation discussed herein, orthotic insert 21 consistsessentially of two zones of material. A first zone located and sized tounderlie the fat pad of heel j and having a corresponding compressionload of 400 to 1,000 psi, and a second zone, anterior to the first zoneand located and sized to underlie mid-foot h, the second zone having acompression load deflection value which is higher than that of the firstzone, selected, for example, from the range of 600 and 1,200 psi. Inpractical terms, this means that the second portion deflects lessreadily than the first portion under comparable force. In this way,insert 21, through a relatively simple construction, includes designsand features to offload vertical force experienced by heel j to mid-footh during a person's gait. The first and second zones formed by portions23, 25, respectively, have an opposing boundary along arcuate surface33, as discussed previously, and the differing rigidities betweenportions 23, 25 thereby form a transition zone 61 between the tworigidities designed into portions 23, 25. As such, this transition zonehas a corresponding compression load deflection between that of the zoneunderlying heel j and that associated with portion 25 at apex region 49.In some applications, transition zone 61 may improve wearer comfortwhile still permitting offloading of vertical force from heel j towardmid-foot h.

Having described the structures and features of insert 21, its use andadvantages are readily apparent. A pair of inserts 21 is placed in acorresponding pair of shoes, lower surface 52 of device 21 beinggenerally placed to oppose the shoe insole, and upper surface 51positioned to underlie the heel and mid-foot of the wearer. Duringwalking, especially during heel strike and contact phase of a person'sgait, the disclosed insert not only decreases the force felt on theheel, but also offloads such force, rapidly transferring the force andcorresponding weight to the middle part of the foot, especially duringthe impact or propulsive phases of the gait. By offloading the heel andtransferring the weight to the mid-foot, force becomes dissipated over amuch larger plantar surface area, decreasing felt impact on the heel andshortening the time the force is affecting the foot.

Among the advantages of the foregoing, decreasing the felt impact andtransferring forces to the larger surface area of the foot and mid-footgenerally decreases or eliminates associated discomfort with a varietyof disorders of the heel and hind-foot, such as those listed earlier inthis disclosure.

While one or more particular implementations have been set out in thisdisclosure, it will be appreciated that various alternatives to thedisclosed structure are likewise contemplated and within the scope ofthis disclosure. For example, although the illustrated implementationmakes use of just two pieces, it will be appreciated that furtherportions of varying materials or durometer may likewise be included.While the forward edge of the device terminates proximal to metatarsalheads, there may be applications where a full insert may be suitable. Itis also contemplated that instead of two separate portions, insert 21may be formed from a single, integral piece formed of one or morematerials with varying durometers, whether horizontally, vertically,laterally, or longitudinally, located at the zones and locations of theheel and mid-foot in accordance with this disclosure.

Still further variations are contemplated by the disclosure herein,which should be understood to extend to the boundaries of the appendedclaims and equivalents thereto.

What is claimed is:
 1. An orthotic insert for footwear to be worn by a person, the insert comprising: a first portion located and sized to underlie the calcaneus of the person's heel; and a second portion anterior to the first portion, the second portion located and sized to underlie the mid-foot and the sagittal plane arch of the mid-foot when the insert is positioned in footwear worn by the person; the insert having medial and lateral edges and the first and second portions extending transversely between the medial and lateral edges; wherein the first portion is composed of a first resiliently compressible material; wherein the second portion is composed of a second resiliently compressible material; wherein the first resiliently compressible material is characterized by a first predetermined durometer value and the second resiliently compressible material is characterized by a second predetermined durometer value, the durometer values being determined according to the 00 scale of ASTM D2240; wherein the first durometer value is lower than the second durometer value; wherein the first and second portions have lower surfaces having coplanar portions defining a lowermost plane of the insert; wherein the first portion has a first upper surface, wherein the second portion has a second upper surface, the second upper surface including a sagittal arch surface defined therein and adapted to underlie the sagittal plane arch of the foot when the insert is positioned in footwear worn by the person, the sagittal arch surface extending from the lateral to the medial edges of the insert, the sagittal arch surface having an uncompressed height relative to the lowermost plane that is substantially the same at both the medial and lateral edges; and wherein, when the insert is positioned in footwear worn by the person, the second portion at the sagittal arch surface is adapted to compress by an amount that is no more than 7 percent of the uncompressed height of the sagittal arch surface.
 2. The orthotic insert of claim 1, wherein the first portion extends distally to define a distal portion sized to extend laterally between the medial and lateral edges of the insert, the first portion extending distally between first and second locations relative to the person's foot when the insert is positioned in footwear worn by the person, the first location underlying the insertion point of the proximal ends of the plantar fascia on the medial tubercle of the calcaneus, the second location underlying the calcaneal cuboid joint, the distal portion terminating at the second location at a distal edge of the first portion, the distal edge positioned adjacent to the sagittal plane arch of the person's foot; wherein the second portion has a posterior portion, the posterior portion opposing the distal portion of the first portion to define a transversely oriented boundary, the transversely oriented boundary extending transversely between the medial and lateral edges of the insert and extending distally at an angle between the upper and lower surfaces of the first and second portions, the angle commencing at the first location and terminating at the second location; and wherein, when the insert is position in footwear worn by the person, the angle commences at the first location of the first portion underlying the insertion point of the proximal ends of the plantar fascia in the medial tubercle and terminates at the distal edge to form a transition zone of durometer value between the durometer values of the first and second portions.
 3. The insert of claim 1, wherein the first durometer value is lower than the second durometer value by an amount ranging from 10 to
 30. 4. The orthotic insert of claim 1, wherein the first portion has a compression load deflection value that is less than the compression load deflection value of the second portion undergoing the same compression load deflection test.
 5. The orthotic insert of claim 1, wherein the first portion has a compression load deflection value of between 400 to 1,000 lbs. per square inch; and wherein the second portion has a compression load deflection value of between 600-1,200 lbs. per square inch.
 6. The orthotic insert of claim 1, wherein the resiliently compressible material of the first portion has a durometer in the range of 70-80, and the second portion has a durometer in the range of 90-100.
 7. The orthotic insert of claim 1, wherein the first and second portions have been sized to correspond, respectively, to underlie the heel and mid-foot of a user selected from the group consisting of men, women and children; wherein the insert has a length extending from a proximal edge extending to a forward edge, wherein the first upper surface underlying the heel and the corresponding first resiliently compressible material extends from the proximal edge distally between 40-45 percent of the length of the insert, and the second, upper surface of the corresponding second, resiliently compressible material extends 55-65 percent of the overall length of the insert.
 8. The insert of claim 1, wherein the resiliently compressible material comprises at least one material selected from the group consisting of thermoset materials, foam, plastic, thermoplastic elastomers, volcanized or thermoset rubber, elastomeric materials, cellular materials, metal, wood, cellulose, and paper.
 9. The insert of claim 1, wherein the lower durometer of the first portion is selected to cause the first portion to deflect more than the second portion at the sagittal arch surface, in response to comparable load, whereby, during heel-strike phases of a gait cycle of the person, vertical force is off-loaded from the heel toward the mid-foot.
 10. The insert claim of 1, further comprising a covering overlying the first and second portions.
 11. The insert claim of 10, wherein the covering comprises a fabric.
 12. An orthotic insert for a person's foot, the foot having lateral and medial sides, the insert comprising: resiliently compressible material sized and shaped to extend transversely between medial and lateral edges to underlie the medial and lateral sides of the person's foot, and extending longitudinally between rear and distal edges to underlie the person's heel and the person's midfoot; wherein the resiliently compressible material consists of first and second portions, the second portion having a durometer value ranging between 10 and 30 higher than the durometer value of the first portion, according to the 00 scale of ASTM D2240; the first portion having a corresponding heel area at a first location underlying the calcaneus of the heel when the insert is within footwear worn by the person, the heel area extending distally to terminate at a forward end of the first portion; wherein the forward end of the first portion extends between the lateral and medial edges of the insert and, when the insert is within footwear worn by the person, the forward end is located on the insert at a second location underlying the person's foot between the insertion point of the plantar fascia and the sagittal plane arch of the person's foot; wherein the second portion extends distally from the first portion to a third location adapted to underlie the mid-foot when the insert is within footwear worn by the person; wherein the second portion has a proximal end opposing the forward end of the first portion to form a boundary between the first and second portions, the boundary extending between the lateral and medial edges, whereby the durometer of the resiliently compressible material of the first portion proximal to the boundary is less than the durometer of the resiliently compressible material of the second portion distal to the boundary; wherein the proximal end of the second portion has a sagittal arch area defined therein, the sagittal arch area located on the insert to underlie the sagittal plane arch of the person's foot when the insert is within footwear being worn by the person; wherein, in response to the weight of the person when wearing footwear with the insert therein, the size, shape and higher durometer of the resiliently compressible material at the sagittal arch area are selected to induce greater supporting force on the sagittal plane arch of the person's foot when wearing footwear with the insert, relative to supporting force induced by the resiliently compressible material at the heel area, whereby vertical force is offloaded from the person's heel toward the person's mid-foot.
 13. The insert of claim 12, wherein the first and second portions have respective upper and lower surfaces, and wherein the boundary between the first and second portions slopes upwardly from the lower surfaces to the upper surfaces.
 14. The insert of claim 12, wherein the forward end of the first portion terminates in a forward edge at the upper surface, the forward edge opposing the sagittal arch area.
 15. The insert of claim 12, further comprising a covering overlying the first and second portions.
 16. The insert claim of 15, wherein the covering comprises a fabric.
 17. An orthotic device for a person's foot, the foot having lateral and medial sides, the device associated with footwear to be worn by the person, the footwear having a sole for contacting a ground plane when worn by the person, the device comprising: lateral and medial edges defining a width configured to underlie the lateral and medial sides of the person's foot when the device is within the footwear worn by the person; a compressible heel portion having a corresponding heel area adapted to underlie the calcaneus of the heel, the heel portion extending transversely between the lateral and medial edges of the device, the heel portion having a length extending from a rear edge to a distal edge and a width extending transversely between the medial and lateral edges; wherein the distal edge is located on the device to underlie a location between the calcaneal cuboid joint and the sagittal plane arch of the person's foot when the device is within footwear being worn by the person; a compressible mid-foot portion extending distally from the heel portion toward the mid-foot, the mid-foot portion having a midfoot area and a sagittal arch area defined within the midfoot area, the mid-foot area adapted to underlie the person's mid-foot, the sagittal arch area adapted to underlie the sagittal plane arch of the person's foot, the sagittal arch area extending transversely between the lateral and medial edges of the device, the sagittal arch area having a proximal edge opposing the distal edge of the heel portion; wherein the heel area is characterized by an uncompressed height relative to the ground plane of the footwear and at a location that would correspond to the location of the calcaneus when the device is within footwear worn by the person; wherein the mid-foot portion is characterized by a maximum uncompressed height relative to the ground plane; wherein the maximum uncompressed height of the mid-foot portion is located within the sagittal arch area; and wherein the uncompressed height of the heel area is greater than the maximum uncompressed height of the mid-foot portion.
 18. The orthotic device of claim 17, wherein the heel area comprises a planar area when uncompressed, the planar area sized and located to underlie the fat pad of the heel when the device is within footwear worn by the person, the planar area, when uncompressed, sloping downwardly to the sagittal arch area when uncompressed.
 19. The orthotic device of claim 17, wherein the device comprises an insert removably placeable within the footwear.
 20. The orthotic device of claim 17, wherein the first and second portions include respective upper and lower surfaces defined to extend between lateral and medial sides of the device, the lower surfaces being substantially planar, the lower surfaces being coplanar with respect to each other; and wherein the first portion has a first transversely oriented, forward surface extending from the lower surface of the first portion, distally and upwardly between the medial and lateral edges to define a slope, the forward surface terminating at the upper surface to define the distal edge of the heel area; and wherein the second portion has a second transversely oriented surface opposing the first transversely oriented surface, from the lateral to the medial sides, extending from the lower surface of the second portion upwardly to the upper surface of the second portion.
 21. The orthotic device of claim 17, wherein the sagittal arch area is defined within the mid-foot area to extend from the distal edge of the first portion by an amount ranging from 0.5 centimeters to 1.5 centimeters. 